Zhongren Zhou

Silicon suboxide (SiO _x ) is a promising anode material for high‐energy‐density lithium‐ion batteries, but its large volume change and low intrinsic conductivity hinder practical application. These issues cause parasitic side reactions with the electrolyte, leading to continuous electrolyte consumption and slow ion/electron transport, thereby limiting achievable capacity and energy density. To address these challenges, this study developed a strategy using lithiated polyacrylic acid (LiPAA) to modify micron SiO _x via spray drying, constructing spherical SiO _x @LiPAA composites. The LiPAA polymer infiltrates the surface of SiO _x , forming a solid spherical structure. It establishes an effective conductive network to enhance electron transport, promotes lithium‐ion desolvation for improved kinetics, and acts as an elastic buffer to maintain structural integrity under high area load. Simultaneously, the polymer promotes a denser, thinner, and LiF‐rich solid electrolyte interface (SEI), inhibiting parasitic reactions and ensuring stable cycling. Electrochemical tests showed the composite retains a reversible specific capacity of 1234.06 mAh g ⁻¹ after 200 cycles at 0.5C. At a high rate of 4.0C, the reversible capacity was 536.2 mAh g ⁻¹ . When paired with a LiFePO ₄ cathode, the full cell maintained 86.4% capacity retention after 500 cycles. This work offers a feasible route to develop high‐performance, low‐cost, and scalable silicon‐based anodes.

Silicon sub‐oxides (SiO _x ) are promising high‐capacity anodes for advanced lithium‐ion batteries but suffer from rapid capacity fade, progressive voltage decay, and inferior rate capability. While monolithic coating strategies (e.g., rigid CVD carbon encapsulation or flexible poly(acrylic acid) (PAA) chemical coupling) partially mitigate volumetric expansion and interfacial instability, their effectiveness is fundamentally constrained by inherent conductivity‐mechanical buffering trade‐offs. This study systematically compares these systems, establishing that carbon layers govern electron transport while PAA matrices reinforce interfacial stabilization. Consequently, this study developes an innovative gradient heterogeneous coating strategy (SiO _x @C/PAA and SiO _x /PAA@C architectures) that resolves the conductivity‐stability paradox through precise coating sequence modulation. Experimental results demonstrate that outer‐layer physicochemical properties dictate overall performance: SiO _x /PAA@C (carbon exterior) delivers superior rate capability (480 mAh g ⁻¹ at 6 A g ⁻¹ ; 120 mAh g ⁻¹ at 4.5 A g ⁻¹ in full cells), while SiO _x @C/PAA (PAA exterior) achieves exceptional cycling stability (89.3% retention after 150 cycles; 81.17% after 650 cycles in full cells). Inner coatings enhance active material stability via microstructural modulation. This approach successfully addresses the tripartite challenges of capacity preservation, rate performance optimization, and industrial scalability, establishing a theoretical framework for hierarchical interface engineering in silicon‐based anodes alongside scalable fabrication protocols for practical implementation.

Silicon suboxide (SiOx) anode materials are sought to substitute graphite-based anodes due to their high theoretical capacity and lower volume expansibility. Present chemical vapor deposition industrial production inevitably produces about 15 wt % submicro SiOx wastes. To improve the reuse of submicro SiOx wastes in a more economical, efficient, and sustainable way, present research focuses on exploring spherical porous SiOx/poly(acrylic acid) (PAA) microparticles via a spray-drying process to enhance resilience and adhesivity. The PAA polymer membrane uniformly coats the SiOx matrix via strong hydrogen bond interactions, providing mechanical strength to whole particles. The availability of polymer also possesses excellent electrochemical stability and adhesion, remaining almost free from pulverization during cycling. In half-cell testing, the synthesized micro SiOx/PAA particles demonstrate a higher initial capacity efficiency of 68% compared to that of submicro SiOx and a high reversible capacity of 1102 mAh g^-1 with a fading rate of 0.036% per cycle after 200 cycles at 2 A g^-1. Even after 1000 ultralong cycles, the capacity still remains above 200 mAh g^-1. The full-cell measurement shows a capacity of 160.25 mAh g^-1 for 600 cycles, suggesting their practicality for industrial production. Microsized SiOx anodes have shown impressive performance, achieving high Coulombic efficiency (>99.8%), exceptional rate capability, and outstanding cycling stability over 600 cycles.

O3‐type cathode material with high theoretical capacity possesses significant potential for sodium ion batteries (SIBs). However, the irreversible phase transition, structural volume change and poor Na⁺ transmission efficiency, caused by Jahn–Teller distortion of Mn³⁺, lead to the inferior cycling lifespan. Herein, the nonequilibrium‐driven local electron spin‐state modulation at Mn site with Sn⁴⁺ substitution is proposed to stabilize the NaNi_0.33Fe_0.33Mn_0.33O₂ cathode. With this, the controlled irreversible phase transition and volume expansion during charge/discharge and fast Na⁺ transportation channel is achieved. Therefore, the modulated NaNi_0.33Fe_0.33Mn_0.33O₂ cathode can contribute to improved capacity of 144.8 mAh g⁻¹ at 0.1 C rate and long‐term cycling over 200 cycles with 80.1% retention by comparison with the counterpart (132.5 mAh g⁻¹ at 0.1 C) and 54.1% retention. Noted that the elevated Na⁺ diffusion kinetics corresponding to high‐rate capability is also demonstrated (93.2 mAh g⁻¹ at 10 C rate). Furthermore, the full battery equipped with hard carbon anode shows an energy density of 381.05 Wh kg⁻¹ and the 76.8% retention after 200 cycles. This work highlights the regulation of electron spin‐state from the insight of modification Jahn–Teller effect would shed a new perception on the design for the advanced layered cathode materials and SIBs.

In this study, molten-salt electrolysis of silica was investigated to identify the role played by electrolytic conditions on the deoxidization depth. Four key conditions that included particle size, electrolytic temperature, working time, and cell voltage were systematically compared using X-ray diffraction, scanning electron microscopy (SEM), field-emission SEM, transmission electron microscopy, and X-ray photoelectron spectroscopy analyses. The results suggest that prolonging the cell voltage is another key factor that determines the reduction process. Based on the given current conditions, the order of effect on the experiment is working time, cell voltage, electrolytic temperature, and particle size. The obtained specimen under optimized condition is Si and Fe–Si alloy composite with silicon porous nanosphere and Fe–Si nanoparticles in a structure that is prepared using 10 nm SiO₂ nanosphere as a raw material at 800 °C for 5 h at a cell voltage of 2.6–2.8 V. The present research provides a promising guidance for practical application using the method of molten-salt electrolysis.